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51.
Dr. Ze-Jie Lv Wei Liu Miaomiao Zhu Zhengqi Chai Junnian Wei Prof. Wen-Xiong Zhang 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(66):16498-16504
Although the reaction chemistry of transition metallacyclopropenes has been well-established in the last decades, the reactivity of rare-earth metallacyclopropenes remains elusive. Herein, we report the reaction of lutetacyclopropene 1 toward a series of unsaturated molecules. The reaction of 1 with one equiv. of PhCOMe, Ar1CHO (Ar1=2,6-Me2C6H3), W(CO)6, and PhCH=NPh provided oxalutetacyclopentenes, metallacyclic lutetoxycarbene, and azalutetacyclopentene via 1,2-insertion of C=O, C≡O, or C=N bonds into Lu−Csp2 bond, respectively. However, the reaction between 1 and Ar2N=C=NAr2 (Ar2=4-MeC6H4) gave an acyclic lutetium complex with a diamidinate ligand by the coupling of one molecule of 1 with two carbodiimides, irrespective of the amount of carbodiimide employed. More interestingly, when 1 was treated with two equiv. of Ar1CHO, the reductive coupling of two C=O bonds was discovered to give a lutetium pinacolate complex along with the release of tolan. Remarkably, the reactivity of 1 is significantly different from that of scandacyclopropenes; these metallacycles derived from 1 all represent the first cases in rare-earth organometallic chemistry. 相似文献
52.
Yung-Shun Su Jih-Jung Chen Ming-Jen Cheng Chee-Yin Chai Aij-Lie Kwan Jheng-Cian Huang Yueh-Hsiung Kuo 《Molecules (Basel, Switzerland)》2021,26(16)
Phytochemical investigation and chromatographic separation of extracts from the actinobacteria strain Saccharomonospora piscinae that was isolated from dried fishpond sediment of Kouhu township, in the south of Taiwan, led to the isolation of three new compounds, saccharpiscinols A–C (1–3, respectively), and three new natural products, namely (2S)-5,7,3′,4′-tetrahydroxy-6,8-dimethylflavanone (4), methyl-4-hydroxy-2-methoxy-6-methylbenzoate (5), and (±)-7-acetyl-4,8-dihydroxy-6-methyl-1-tetralone (6). Compounds 4–6 were reported before as synthesized products, herein, they are reported from nature for the first time. The structures of the new compounds were unambiguously elucidated on the basis of extensive spectroscopic data analysis (1D- and 2D-NMR, MS, and UV) and comparison with literature data. The effect of some isolates on the inhibition of NO production in lipopolysaccharide-activated RAW 264.7 murine macrophages was evaluated. Saccharpiscinol A showed inhibitory activities against LPS-induced NO production. 相似文献
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Huachang Chen Dongying YuanYiya Li Mingjie DongZhihua Chai Juan KongGuoqi Fu 《Analytica chimica acta》2013
Surface imprinting over nanosized support materials is particularly suitable for protein templates, considering the problems with mass transfer limitation and low binding capacity. Previously we have demonstrated a strategy for surface protein imprinting over vinyl-modified silica nanopartiles with lysozyme as a model template by polymerization in high-dilution monomer solution to prevent macrogelation. Herein, the synthesis process was further studied toward enhancement of the imprinting performance by examining the effect of several synthesis conditions. Interestingly, the feed crosslinking degree was found to have a great impact on the thickness of the formed imprinting polymer layers and the recognition properties of the resulting imprinted materials. The imprinted particles with a crosslinking degree up to 50% showed the best imprinting effect. The imprinting factor achieved 2.89 and the specific binding reached 23.3 mg g−1, which are greatly increased compared to those of the lowly crosslinked imprinted materials reported previously. Moreover, the relatively high crosslinking degree led to no significant retarding of the binding kinetics to the imprinted particles, and the saturated adsorption was reached within 10 min. Therefore, this may be a promising method for protein imprinting. 相似文献
56.
SOLAR SPECTRAL IRRADIANCE IN THE VISIBLE AND INFRARED REGIONS 总被引:1,自引:0,他引:1
Abstract— The analytical formulas previously developed for estimating the spectral irradiance reaching the ground in the ultraviolet are extended into the visible and infrared(350–3000 nm). This approach has two distinct features: (1) all physical inputs for calculating the direct irradiance are given in analytical form, and (2) the diffuse spectral irradiance (skylight) is calculated using dimensionless ratios which relate it to the direct irradiance. In common with other approaches, the global spectral irradiance for arbitrary ground reflectivity is calculated from the sum of the direct and diffuse spectral irradiances and a divisor which depends upon the ground and air spectral reflectivities. The global spectral irradiance on a tilted surface may also be calculated in terms of the above quantities and two angles. As in the case of the ultraviolet, the formulas presented are intended for photobiological applications. 相似文献
57.
Owing to the fast economic growing and the concern over greenhouse gases and air pollution,the development of nuclear energy is one important option to meet the expanded energy consumption in our future.To achieve that goal,continuing and reliable supplies of uranium are critical to future nuclear power projects.As is well known,global terrestrial reserves of uranium are limited and the deposits in China are relatively small.Given the projected big growth in nuclear power in the future,reliable supply of uranium at a reasonable price is essential for China. 相似文献
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59.
通过调控酸碱浓度, 在水热条件下得到了金红石、锐钛矿、板钛矿、钛酸钠等一系列TiO2/钛酸盐产物. 对上述TiO2、酸洗处理后的钛酸盐等一系列不同晶型、不同形貌的样品进行焙烧处理, 系统性地研究焙烧温度的逐渐升高对产物晶型转变和形貌演化的规律性影响. 给出了水热酸碱浓度以及焙烧温度两个因素与TiO2/钛酸盐纳米材料晶型和形貌变化行为关系的二维示意图. 依据奥斯特瓦尔德阶梯规则、经典热力学理论以及定向附着生长机理, 对TiO2/钛酸产物的晶型晶体生长、晶型转变和形貌演化机理进行了探讨. 相似文献
60.
Chen Chen Xiangheng Niu Yan Chai Hongli Zhao Minbo Lan Yonggang Zhu Gang Wei 《Electroanalysis》2013,25(6):1446-1452
This work presents a disposable bismuth‐antimony film electrode fabricated on screen‐printed electrode (SPE) substrates for lead(II) determination. This bismuth‐antimony film screen‐printed electrode (Bi‐SbSPE) is simply prepared by simultaneously in situ depositing bismuth(III) and antimony(III) with analytes on the homemade SPE. The Bi‐SbSPE can provide an enhanced electrochemical stripping signal for lead(II) compared to bismuth film screen‐printed electrodes (BiSPE), antimony film screen‐printed electrodes (SbSPE) and bismuth‐antimony film glassy carbon electrodes (Bi‐SbGC). Under optimized conditions, the Bi‐SbSPE exhibits attractive linear responses towards lead(II) with a detection limit of 0.07 µg/L. The Bi‐SbSPE has been demonstrated successfully to detect lead in river water sample. 相似文献